Mechanical motion devices include, but are not limited to: pneumatic arms, robots, and other mechanical moving elements. Safety features for mechanical motion devices are described in the patent literature, including in the following patent publications: U.S. Pat. Nos. 4,639,184; 5,484,219; 5,782,445; 5,954,446; 6,847,181 B2; and PCT Patent Publications: WO 2003/013783 A1; WO 2006/117025; and WO 2009/080373 A1. Some of these publications describe break-away clutches, couplings, and mechanisms to protect the mechanical motion device and/or the end of arm tooling in the event of a collision with another object. Several of these mechanisms are directed to decoupling a portion of the mechanical motion device from the remainder of the device. For example, such mechanisms may decouple a robotic arm from the remainder of the robot.
Collaborative robots (or CoBots) are robots that are intended to work alongside humans in a shared workspace without traditional safety guarding or cages. CoBots are a relatively new technology and provide unique safety problems. As such, evolving industry regulations are requiring that CoBot safety does not solely rely on the force detection inherent to the CoBot. While some of the publications listed above describe collision safety features that are designed to stop the movement of a mechanical motion device when the mechanical motion device makes contact with an object that results in a force being applied to the mechanical motion device, such a collision detection mechanism may not be suitable for devices which come into contact with a human. The forces may be too high, and the end of arm tool may be too rigid which may cause the person in the vicinity of the mechanical moving device to be injured if they are relying on such a collision detection mechanism for their personal safety. Therefore, it is believed that such collision detection mechanisms would not be considered to be safety rated for human protection. Currently, in order to compensate for the shortcomings of such mechanical motion devices, humans working in close proximity with mechanical motion devices are often placed behind safety guarding or cages.
The search for improved safety features for mechanical motion devices has, therefore, continued. There is a need for a safety device for mechanical motion device that is capable of isolating the energy of the mechanical motion device from a collision with an external element or person. Further, there is a need for a safety device for a mechanical motion device that can be safety rated for human protection in lieu of traditional safety guarding or cages.